Quarterly report pursuant to Section 13 or 15(d)

Convertible Preferred Stock and Stockholders' Equity (Deficit) - Warrants for shares of common stock (Details)

v3.21.2
Convertible Preferred Stock and Stockholders' Equity (Deficit) - Warrants for shares of common stock (Details)
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 04, 2021
USD ($)
$ / shares
shares
Apr. 23, 2020
$ / shares
shares
Jun. 30, 2021
USD ($)
$ / shares
shares
Jan. 31, 2021
USD ($)
$ / shares
shares
Apr. 30, 2020
USD ($)
$ / shares
shares
Mar. 31, 2020
USD ($)
$ / shares
shares
Jun. 30, 2021
USD ($)
$ / shares
shares
Mar. 31, 2021
shares
Jun. 30, 2020
USD ($)
Jun. 30, 2021
USD ($)
$ / shares
shares
Jun. 30, 2020
USD ($)
Dec. 31, 2020
$ / shares
shares
Apr. 23, 2021
Nov. 09, 2020
shares
Apr. 18, 2019
shares
Class of Stock [Line Items]                              
Deemed dividend from warrant repricing             $ 0   $ 134,000 $ 0 $ 134,000        
Proceeds from Warrant Exercises                   $ 0 $ 37,000        
Lisa Walsh                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares 187,500                           12,756
Warrant term 5 years 4 months                            
Common Shares                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares                           236,369  
Warrants to purchase shares of common stock for cash | shares     250,000                        
Issuance of common stock upon warrant exchanged | shares             1,360,244 2,086,251              
June 4th Purchase Agreement                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares     2,275,000       2,275,000     2,275,000          
Exercise price of warrants | $ / shares     $ 2.55       $ 2.55     $ 2.55          
Fair value of warrant     $ 3,153,000       $ 3,153,000     $ 3,153,000          
Common Stock Price | $ / shares     $ 2.52       $ 2.52     $ 2.52          
June 8th Purchase Agreement                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares     2,040,000       2,040,000     2,040,000          
Exercise price of warrants | $ / shares     $ 2.61       $ 2.61     $ 2.61          
Fair value of warrant     $ 2,375,000       $ 2,375,000     $ 2,375,000          
Common Stock Price | $ / shares     $ 2.25       $ 2.25     $ 2.25          
April 2020 public offering                              
Class of Stock [Line Items]                              
Exercise price of warrants | $ / shares   $ 3.25     $ 0.01                    
Fair value of warrant         $ 475,000                    
Common Stock Price | $ / shares         $ 2.50                    
Combined shares price | $ / shares   $ 3.24     $ 3.25                    
Deemed dividend from warrant repricing         $ 2,606,000         $ 134,000          
Proceeds from Issuance of Warrants         $ 4,750                    
Issuance of common stock upon warrant exchanged | shares         475,000                    
Warrant term                         5 years    
Warrant                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares     281,000       281,000     281,000          
Proceeds from Issuance of Warrants             $ 889,000                
Warrant | Lisa Walsh                              
Class of Stock [Line Items]                              
Exercise price of warrants | $ / shares $ 3.00                            
Fair value of warrant $ 570,000                            
Common Stock Price | $ / shares $ 4.77                            
Warrant | Common Shares                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares     1,000,000       1,000,000     1,000,000          
Exercise price of warrants | $ / shares     $ 4.46       $ 4.46     $ 4.46          
Fair value of warrant     $ 579,000       $ 579,000     $ 579,000          
Common Stock Price | $ / shares     $ 4.50       $ 4.50     $ 4.50          
Net proceeds     $ 2,300,000                        
Warrant term     5 years       5 years     5 years          
Warrant | January 2021 [Member]                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares       1,221,675                      
Warrants to purchase shares of common stock for cash | shares       305,419                      
Exercise price of warrants | $ / shares       $ 4.20                      
Fair value of warrant       $ 567,000                      
Common Stock Price | $ / shares       $ 3.85                      
Proceeds from Warrant Exercises       $ 2,900,000                      
Warrant term       5 years                      
March 2020 Warrant                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares           227,679                  
Exercise price of warrants | $ / shares           $ 6.40                  
Fair value of warrant           $ 625,000                  
Common Stock Price | $ / shares           $ 5.40                  
March 2020 Maxim Warrant                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares           20,400                  
Prefunded common stock purchase warrants | April 2020 public offering                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares         475,000                    
Common stock purchase warrants | April 2020 public offering                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares   475,000     1,525,000                    
Exercise price of warrants | $ / shares         $ 3.25                    
April 2020 Maxim Warrant                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares     15,000   100,000   15,000     15,000   15,000      
Exercise price of warrants | $ / shares         $ 3.90                    
Fair value of warrant         $ 106,000                    
Common Stock Price | $ / shares     $ 15.80   $ 2.50   $ 15.80     $ 15.80   $ 15.80      
Combined shares price | $ / shares                   $ 0.20   $ 0.20      
Issuance of common stock upon warrant exchanged | shares                   20,722   20,722      
April 2020 Maxim Warrant | April 2020 public offering                              
Class of Stock [Line Items]                              
Warrants to purchase shares of Common Stock | shares   100,000     291,000                    
Exercise price of warrants | $ / shares         $ 3.90                    
Dividend Yield | June 4th Purchase Agreement                              
Class of Stock [Line Items]                              
Measurement input     0.0       0.0     0.0          
Dividend Yield | June 8th Purchase Agreement                              
Class of Stock [Line Items]                              
Measurement input     0.0       0.0     0.0          
Dividend Yield | April 2020 public offering                              
Class of Stock [Line Items]                              
Measurement input         0.0                    
Dividend Yield | Warrant | Lisa Walsh                              
Class of Stock [Line Items]                              
Measurement input 0.0                            
Dividend Yield | Warrant | Common Shares                              
Class of Stock [Line Items]                              
Measurement input     0.0       0.0     0.0          
Dividend Yield | Warrant | January 2021 [Member]                              
Class of Stock [Line Items]                              
Measurement input       0.0                      
Dividend Yield | March 2020 Warrant                              
Class of Stock [Line Items]                              
Measurement input           0.0                  
Dividend Yield | April 2020 Maxim Warrant                              
Class of Stock [Line Items]                              
Measurement input         0                    
Volatility | June 4th Purchase Agreement                              
Class of Stock [Line Items]                              
Measurement input     64.0       64.0     64.0          
Volatility | June 8th Purchase Agreement                              
Class of Stock [Line Items]                              
Measurement input     64.0       64.0     64.0          
Volatility | April 2020 public offering                              
Class of Stock [Line Items]                              
Measurement input         64.0                    
Volatility | Warrant | Lisa Walsh                              
Class of Stock [Line Items]                              
Measurement input 60.7                            
Volatility | Warrant | Common Shares                              
Class of Stock [Line Items]                              
Measurement input     60.7       60.7     60.7          
Volatility | Warrant | January 2021 [Member]                              
Class of Stock [Line Items]                              
Measurement input       60.1                      
Volatility | March 2020 Warrant                              
Class of Stock [Line Items]                              
Measurement input           61.0                  
Volatility | April 2020 Maxim Warrant                              
Class of Stock [Line Items]                              
Measurement input         64                    
Risk-free rate of interest | June 4th Purchase Agreement                              
Class of Stock [Line Items]                              
Measurement input     0.45       0.45     0.45          
Risk-free rate of interest | June 8th Purchase Agreement                              
Class of Stock [Line Items]                              
Measurement input     0.32       0.32     0.32          
Risk-free rate of interest | April 2020 public offering                              
Class of Stock [Line Items]                              
Measurement input         0.37                    
Risk-free rate of interest | Warrant | Lisa Walsh                              
Class of Stock [Line Items]                              
Measurement input 0.78                            
Risk-free rate of interest | Warrant | Common Shares                              
Class of Stock [Line Items]                              
Measurement input     0.77       0.77     0.77          
Risk-free rate of interest | Warrant | January 2021 [Member]                              
Class of Stock [Line Items]                              
Measurement input       0.45                      
Risk-free rate of interest | March 2020 Warrant                              
Class of Stock [Line Items]                              
Measurement input           0.38                  
Risk-free rate of interest | April 2020 Maxim Warrant                              
Class of Stock [Line Items]                              
Measurement input         0.37                    
Term (Years) | June 4th Purchase Agreement                              
Class of Stock [Line Items]                              
Fair Value Expected Term                   5 years 6 months          
Term (Years) | June 8th Purchase Agreement                              
Class of Stock [Line Items]                              
Fair Value Expected Term                   5 years 6 months          
Term (Years) | April 2020 public offering                              
Class of Stock [Line Items]                              
Fair Value Expected Term         5 years                    
Term (Years) | Warrant | Lisa Walsh                              
Class of Stock [Line Items]                              
Fair Value Expected Term 5 years 4 months 24 days                            
Term (Years) | Warrant | Common Shares                              
Class of Stock [Line Items]                              
Fair Value Expected Term     5 years                        
Term (Years) | Warrant | January 2021 [Member]                              
Class of Stock [Line Items]                              
Fair Value Expected Term       5 years                      
Term (Years) | March 2020 Warrant                              
Class of Stock [Line Items]                              
Fair Value Expected Term           5 years                  
Term (Years) | April 2020 Maxim Warrant                              
Class of Stock [Line Items]                              
Fair Value Expected Term         5 years                    
Series A Preferred Stock | Lisa Walsh                              
Class of Stock [Line Items]                              
Issuance of common stock upon warrant exchanged | shares             187,500